1. Field of the Invention
The present invention relates to a method of plant tissue and cell culture and more particularly to a method which enables an efficient cultivation of tissue, taken out of an individual plant body or cultivated in a successive cultivation, or plant cells.
2. Description of the Prior Art
When a piece of tissue cut out of a plant body exhibiting relatively rapid growth, such as undifferentiated shoot appex, root cambium and so on, is cultivated in an artificial culture medium, callus formation, which is a phenomenon of undifferentiated cell multiplication, and formation of differentiated foliate parts and roots are observed separately or simultaneously. In such a plant tissue culture, it is often attempted to facilitate culture growth by addition of, coconut milk, yeast extract and the like. Such growth facilitation is limited to causing proliferation of the callus. Therefore, it has not been possible to produce a differentiated plant body without employing any additional measure. Accordingly, it has heretofore been a common practice to incorporate additional measures for facilitating the differentiation, such as for example, irradiation of ultraviolet rays and addition of phytohormones such as indoleacetic acid, benzyladenine and the like in adequate proportion with each other. However, by these prior art methods for accelerating differentiation, the problems have arisen that these methods are difficult to control and, in particular, that synthetic phytohormones may either promote or retard the differentiation depending upon the amount added.